Toner and method of manufacturing toner

Abstract

A toner containing a mother toner particle containing at least two kinds of resins having a polyester skeleton, and a coloring agent, and a releasing agent, wherein the mother toner particle has a core and a shell layer thereon, and no peak that derives from magnesium, calcium, or aluminum in the mother toner particle is observed in a qualitative analysis using an X-ray fluorescence measuring instrument.

1 . A toner comprising:
 a mother toner particle comprising:
 at least two kinds of resins having a polyester skeleton; and 
 a coloring agent; and 
   a releasing agent,   wherein the mother toner particle has a core and a shell layer thereon, and no peak that derives from magnesium, calcium, or aluminum in the mother toner particle is observed in a qualitative analysis using an X-ray fluorescence measuring instrument.   
     
     
         2 . The toner according to  claim 1 , wherein the shell layer completely covers the core and has an average thickness of from 1/160 to 1/25 based on a number average particle diameter of the toner. 
     
     
         3 . The toner according to  claim 2 , wherein the average thickness of the shell layer and a glass transition temperature Tg of material of the shell layer satisfy the following relationship:
   110 −Ts<W< 2×(155 −Ts ),
   
       where Ts represents the glass transition temperature Tg (° C.) of the shell layer and W represents the average thickness (nm) of the shell. 
     
     
         4 . The toner according to  claim 1 , wherein the core comprises a first resin having a first polyester skeleton, and material of the shell layer comprises a second resin having a second polyester skeleton. 
     
     
         5 . The toner according to  claim 4 , wherein the first resin and the second resin are incompatible with each other. 
     
     
         6 . The toner according to  claim 4 , wherein the core further comprises a modified polyester resin having at least one of a urethane group and a urea group. 
     
     
         7 . The toner according to  claim 6 , wherein the modified polyester resin is elongated or cross-linked by reaction between a modified polyester resin having an isocyanate group at an end thereof and an amine. 
     
     
         8 . The toner according to  claim 1 , wherein the releasing agent is paraffin wax, Fischer-Tropsch wax, or polyethylene wax. 
     
     
         9 . A development agent comprising:
 the toner of  claim 1 ; and   an optional carrier.   
     
     
         10 . An image formation method comprising:
 charging a surface of an image bearing member uniformly;   writing a latent electrostatic image on the surface of the image bearing member by irradiating the surface of the image bearing member based on image data;   forming a layer of a development agent comprising the toner of  claim 1  having a thickness regulated by a layer thickness regulation member on the surface of the image bearing member;   developing the latent electrostatic image with the development agent comprising the toner of  claim 1  to obtain a visualized image;   transferring the visualized image on the surface of the image bearing member to a transfer medium; and   fixing the visualized image on the transfer medium.   
     
     
         11 . A method of manufacturing a toner comprising:
 dissolving or dispersing at least a first resin having a first polyester skeleton, a releasing agent, and a coloring agent in an organic solvent to obtain a lysate or dispersion matter;   forming core particles by suspending the lysate or dispersion matter in an aqueous medium to obtain a liquid suspension in which the core particles are dispersed in the aqueous medium;   preparing a liquid dispersion of particulates comprising a second resin having a second polyester skeleton;   forming a shell layer on the core particles by adding the liquid dispersion of particulates comprising a second resin having a second polyester skeleton to the liquid suspension; and   removing the organic solvent.   
     
     
         12 . The method of manufacturing a toner according to  claim 11 , wherein, in the step of forming a shell layer, the second resin is dissolved in an organic solvent and precipitates on a surface of the core particles to make the shell layer have a successive structure. 
     
     
         13 . The method of manufacturing a toner according to  claim 11 , wherein the aqueous medium comprises a surface active agent. 
     
     
         14 . The method of manufacturing a toner according to  claim 11 , wherein the step of removing the organic solvent is conducted before the step of forming a shell layer. 
     
     
         15 . The method of manufacturing a toner according to  claim 11 , wherein the particulate formed of the second resin has a volume average particle diameter of 0.2 μm or smaller. 
     
     
         16 . The method of manufacturing a toner according to  claim 11 , wherein the step of removing the organic solvent is conducted after the step of forming a shell layer on the core particles. 
     
     
         17 . The method of manufacturing a toner according to  claim 11 , wherein, in the step of forming the shell layer, the shell layer is formed with heating the liquid suspension to a glass transition temperature Tg of the second resin at highest.